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        검색결과 9

        1.
        2020.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 규칙적인 태권도 트레이닝이 비만 중년 여성의 뇌신경성장인자 및 인지기능에 미치는 영향을 알아보는데 목적이 있었다. 본 연구를 위하여 중년 비만 여성 33명이 연구대상자로 선정되었으며, 연구대상자들은 태권도 그룹(TG, n=15)과 대조그룹(CG, n=18)에 무선 배정되었다. 태권도 그룹은 16 주간 일주일에 5번 태권도 트레이닝을 실시하였으며, 두 그룹 모두 트레이닝 전과 후 각각 brain-derived neurotrophic factor(BDNF), vascular endothelial growth factor(VEGF), insulin-like growth factor-1(IGF-1) 농도 검사와 Stroop Color and Word test를 실시하였다. 연구 결과 태권도 그룹의 BDNF와 IGF-1이 트레이닝 후 유의하게 증가한(p<.05) 반면 VEGF와 Stroop Color and Word Test 결과 는 유의한 차이가 나타나지 않아 규칙적인 태권도 트레이닝이 비만 중년 여성의 뇌신경영양인자에는 긍정 적이지만 뇌 인지기능에는 영향이 없는 것으로 나타났다.
        4,000원
        2.
        2019.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study performed a numerical analysis of a 3D unsteady viscous flow in order to investigate ship motion responses running through regular waves of the platform supply vessel. The feasibility of numerical analysis was tested under the three regular wave conditions of the KRISO container ship (KCS) suggested at the 2010 Gothenburg CFD Workshop. The resulting resistance coefficient, heave motion, and pitch angle were compared with the model test of the harmonic analysis. Also, the ship motion response characteristics of the platform supply vessel were performed using the proven method of the KRISO container ship (KCS). The ship motions including the resistance coefficient, heave motion, and pitch angle according to the time series were investigated via harmonic analysis under regular waves condition of λ/LPP=1.87 and HS=0.078m
        4,000원
        3.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 남자 대학생을 대상으로 12주간의 규칙적인 태권도 운동이 체구성, 체력, 뇌파활성 및 뇌신경성장인자(BDNF, IGF-1, NGF)에 미치는 영향을 규명하는데 목적이 있었다. 이를 위해 의학적 질환이 없는 대학생 24명을 대조그룹(CG), 유산소 트레이닝 그룹(ATG) 그리고 태권도 트레이닝 그룹(TTG)에 각각 8명씩 무선 배정하여 연구를 실시하였다. 12주 유산소 및 태권도 트레이닝은 주 3회 실시되었으며, 운동강도와 시간은 4주단위로 조정되었다. 뇌파활성 검사 및 채혈은 12주 유산소 및 태권도 트레이닝 전과 후 각각 실시되었으며, 그룹과 시기에 따른 체력요인 및 생화학성분에 대한 차이를 검증하기 위하여 채혈시점을 반복 측정하는 이원변량분석(two-way repeated ANOVA)을 실시하였다. 이에 대한 연구결과는 다음과 같다. 12주간의 유산소 및 태권도 트레이닝은 신체구성과 뇌파활성에 영향을 미치지 못한 것으로 나타났다. 그러나 유산소 트레이닝과 태권도 트레이닝 모두 체력요소 중 평형성을 증가시키는 것으로 나타났으며(p<.05), 12주 유산소 트레이닝은 뇌신경성장인자인 BDNF를 증가시키는 것으로 나타났다(p<.05). 이상의 결과 12주 유산소 운동은 체력과 뇌신경영양인자에 긍정적인 효과가 있는 반면 태권도 운동은 뇌파활성화 및 뇌신경영양인자에 영향을 미치지 못한 것으로 나타났다.
        4,200원
        5.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In an effort to find the optimum porous of Taewoo through the mathematical model 2 - dimensional tank water experiment among the approached to a problem related to ocean engineering, this study analyzed the porosity by dividing it into 9 cases. As the wave penetrates through the longitudinal porous of the Taewoo model, it was found that there is a wave energy loss because of the phenomenon of the separation of the porous due to the eddy. Looking into the general tendency based on the wave-height meter (probe) data, it was found that the shorter wavelength and higher frequency area, the more reflection coefficients increased, but in contrast, the longer wavelength and lower frequency area, the transmission coefficients showed the increasing trend and energy dissipation was in a similar way with reflection coefficients. In addition, it was found that the bigger the porosity was, the narrower distribution range of reflection coefficients was, and the more its average value decreased. On the other hand the transmission coefficients in direct opposition to reflection was found to show the wider range and the more gradual increase in the average value as porosity was the bigger around the average value. In contrast, energy dissipation rate was found to increase linearly as porosity increased the more around the porosity of 0.2518 but it decreased gradually around the peak point. Through the above results, it is judged that the porous of optimum in the longitudinal direction of the Taewoo model perforated plate was about 2.6cm because it was found that the porosity which produced the lowest reflection and transmission coefficient and the highest energy dissipation. As a result of comparing this to the case where there was no porosity at all, it showed the function of wave absorbing about 31.60%.
        4,000원
        6.
        2013.02 KCI 등재 서비스 종료(열람 제한)
        Since most merchant vessels are mainly influenced by the added resistance in an actual sea, they could be navigated more efficiently if this added resistance could be precisely predicted and then effectively reduced. In this paper, we have computed the effective horsepower based on the resistance performance in still water and then calculated the added resistance in regular wave in order to estimate a ship's propulsion performance on a voyage. Firstly, we have performed experiments using a model of KCS in a circulating water channel to estimate the flow characteristics around a container ship and the ship's resistance in still water. Then we have calculated the motion response function in regular wave as well as the values for the increase in resistance, and evaluated the ship's motion performance in waves according to the calculated response function. It was found that the resistance in waves increased because the ship's motion response value became larger as the ship's speed increased in the case of head sea. The effect of the added resistance could be reduced by maneuvering the ship to the encounter angle of 120˚ in areas of long wavelengths and to head sea in areas of short wavelengths.
        7.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        The primary wave energy conversion by a three-dimensional bottom-mounted oscillating water column (OWC) wave power device in regular waves has been studied. The linear potential boundary value problem has been solved following the boundary matching method. The optimum shape parameters such as the chamber length and the depth of the front skirt of the OWC chamber obtained through two-dimensional numerical tests in the frequency domain have been applied in the design of the present OWC chamber. Time-mean wave power converted by the OWC device and the time-mean second-order wave forces on the OWC chamber structure have been presented for different wave incidence angles in the frequency-domain. It has been shown that the peak period of Pm for the optimum damping parameter coincides with the peak period of the time.mean wave drift force when γ=0.
        8.
        2012.02 서비스 종료(열람 제한)
        본 연구에서는 수치실험을 통하여 규칙파의 주기와 파고를 변화시키면서 수리적 특성을 분석하였다. 수치해석에 사용한 모형의 지배방정식으로는 Navier-Stokes 방정식을 사용하였다. 또한, 자유수면의 변위를 정확하게 해석하기 위하여 VOF기법을 적용하였다. 수치모형실험을 통하여 수중방파제의 기울기 입사파의 주기와 파고 그리고 수중방파제의 유공율을 변화시키면서 월파유량 및 수리적 특성을 연구하였다. 연구결과 불투수성 수중방파제보다 투수성 수중방파제에서 월파유량을 더욱 저감시킴을 알 수 있었으며, 주기가 크고 파고가 클수록 월파유량이 증가함을 알 수 있었다.
        9.
        2000.03 KCI 등재 서비스 종료(열람 제한)
        In the country where the population concentrates in the metropolis with the narrow land, development of the ocean space is necessary. Recently, mega-float offshore structure has been studied as one of the effective utilization of the ocean space. And very large floating structures are now being considered for various applications such as floating airports, offshore cities and so on. This very large structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. And it is necessary to examine the effect of ocean wave external force received from the natural environment. In this study, the mat-type large floating structure is made to be analytical model. And the analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method in the fluid division. The validity of analysis method is verified in comparison with the experimental result in the Japan Ministry of Transport Ship Research Institution. In order to know the characteristics of the dynamic response of the large floating structures, effects of wavelength, bending rigidity of the structure, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.